Littelfuse FLSR-25 FLSR025, 25 Amp, Dual Element Time-Delay Class RK5 Fuse 25 Amp (25A), 600VAC/300VDC Dual Element Time-Delay Class RK5 Fuse This Littelfuse FLSR-25 or FLSR-25 or FLSR025 could be used to substitute for Bussmann FRS-R-25 and Ferraz Shamwut/Mersen TRS-25R